干扰环境下窄带信号时反算子分解聚焦性能分析

近几年来,无论是理论分析还是海上试验,都验证了时反算子分解可实现有选择性的聚焦和目标检测.然而,这些分析和试验都是建立在信噪(混)比很高的前提下的,因此,需要对时反算子分解在于扰环境下的使用进行评估.利用传播模型和混响模型产生回波和混响,研究目标处的聚焦.结果显示,在噪声限制条件下,随着信噪比的降低,聚焦点处的能量逐渐降低;在混响限制条件下,如果选择的特征向量合适,即使在信混比较低的情况下,聚焦性能下降也是比较小的,这点为时反算子分解在低信混比情况下的应用提供了保障.

Decomposition and retrofocusing performance of time reversal operator of narrowband signal without interference

Recent theoretical analysis and experiments have demonstrated that decomposition of the time reversal operator(DORT) can achieve selective focusing and target detection.However,most of these analysis and oceanic experiments were based on the assumption that the signal to noise(reverberation) ratio is high.Therefore,if we use decomposition of time reversal operator technology in noisy environments,an evaluation is indispensable.For this purpose,we generate echoes and reverberation with a propagation model and a reverberation model in order to investigate the focusing performance at the proximity of target.Simulation results showed that,in noisy-limited environment,the energy at the prescribed retrofocusing location decreases with decreasing S/N ratio;however,in reverberation-limited environment,it was found that the decrease of retrofocusing performance is very small even at lower signal-to-reverberation ratio,if a proper eigenvector is chosen.This outcome provides a basis for effective application of time reversal operator techniques in a low signal-to-noise ratio environment.